Systems and methods for identifying different types of traction motors in a vehicle system

ABSTRACT

A control system including a measurement module configured to receive motor measurements that represent operating parameters of plural traction motors of a common vehicle system as the vehicle system propels along a route. The control system also includes an analysis module configured to compare the motor measurements to an expected measurement. The expected measurement corresponds to a designated motor type. The analysis module is configured to determine that at least one of the traction motors is different from the designated motor type based on comparing the motor measurements to the expected measurement.

BACKGROUND

Embodiments of the subject matter described herein relate to systems andmethods for determining operating parameters for traction motors in avehicle system.

At least some known vehicle systems have propulsion systems that includemultiple traction motors. The traction motors are operated as a group tocollectively propel the vehicle system along a route. For instance,various propulsion systems have been developed for locomotives. In onetype of propulsion system, the fraction motors are individuallycontrolled to propel the locomotive along the designated route. Each ofthe traction motors may be energized by a separate inverter that isindividually controlled to adjust an excitation frequency of therespective traction motor. The excitation frequency controls therotation of the traction motor, which drives a corresponding axle thatis coupled to a wheel of the locomotive. Although each of the tractionmotors can be controlled individually, the propulsion system coordinatesoperation of the traction motors to achieve a total tractive effort forthe locomotive. This type of propulsion system may be referred to as a“per-axle” system, because each axle is driven by anindividually-controlled traction motor.

In another type of propulsion system, a set of traction motors aresupported by a common truck. The traction motors of the truck may be inparallel or in series and energized by a common inverter. As such, eachof the traction motors receives the same excitation frequency from theinverter. Assuming that each of the traction motors is of the same motortype (e.g., designed to provide the same motor performance) and thewheel diameters are equal, the traction motors supply an equal amount oftractive effort because the traction motors receive the same excitationfrequency. Locomotives having this type of propulsion system typicallyinclude two trucks. This type of propulsion system is referred to as a“per-truck” system, because the multiple traction motors of the truckare controlled by a single inverter.

In many cases, the traction motors for one type of propulsion system aredesigned to provide a designated motor performance, which may differfrom the motor performances of other propulsion systems. By way ofexample, in per-truck systems, it is generally desirable to havetraction motors with high resistance rotors. The overall performance ofa per-truck system can be sensitive to differences in wheel diameters.Although the traction motors receive the same excitation frequency, thetraction motors will provide different amounts of torque if the wheeldiameters of the wheels that are coupled to the traction motors areunequal. This may lead to undesirable motor heating, motor losses,and/or reduced performance. Traction motors having high resistancerotors are used in per-truck systems because such traction motors reducethe sensitivity of the propulsion system to unequal wheel diameters.Although per-axle systems may also have wheels with different diameters,the per-axle systems are capable of individually controlling the axlesto reduce the negative effects of the unequal wheel diameters. With thesensitivity to unequal wheel diameters being less of a concern, tractionmotors in per-axle systems are permitted to use low resistance rotors,which can be more efficient than high resistance rotors.

In the past, railroads typically used locomotives having the same typeof propulsion system and, consequently, the same type of traction motor.Recently, however, railroads have begun to use different types ofpropulsion systems. During the lifetime operation of a locomotive, thetraction motors of the propulsion system may be replaced. It may bepossible that the traction motor configured for one type of propulsionsystem will be installed into a propulsion system of another type. Ifthis occurs, it may not be readily apparent to the operator or thecontrol system of the locomotive that the traction motor is unsuitable.Nevertheless, continued operation of the locomotive with the improperfraction motor may compromise the overall performance of the propulsionsystem, increase a likelihood of motor failure, or cause other unwantedeffects to the fraction motor or the propulsion system.

BRIEF DESCRIPTION

In an embodiment, a control system is provided that includes ameasurement module configured to receive motor measurements thatrepresent operating parameters of plural traction motors of a commonvehicle system as the vehicle system propels along a route. The tractionmotors may be energized by a common power source and be electricallyparallel with respect to one another. The control system also includesan analysis module configured to compare the motor measurements to anexpected measurement. The expected measurement corresponds to adesignated motor type. The analysis module is configured to determinethat at least one of the traction motors is different from thedesignated motor type based on comparing the motor measurements to theexpected measurement.

In an embodiment, a method is provided that includes controlling pluraltraction motors of a vehicle system to propel the vehicle system along aroute. The traction motors may be energized by a common power source andbe electrically parallel with respect to one another. The method alsoincludes receiving motor measurements that represent operatingparameters of the traction motors as the vehicle system propels alongthe route. The method also includes comparing the motor measurements toan expected measurement. The expected measurement corresponds to adesignated motor type. The method also includes determining that atleast one of the traction motors is different from the designated motortype based on comparing the motor measurements to the expectedmeasurement.

In an embodiment, a control system is provided that includes ameasurement module configured to receive motor measurements thatrepresent operating parameters in plural traction motors of a commonvehicle system as the vehicle system propels along a route. The tractionmotors may be energized by a common power source and be electricallyparallel with respect to one another. The control system also includesan analysis module that is configured to compare the motor measurementsto one another. The analysis module is configured to determine that thetraction motors include different motor types based on comparing themotor measurements to one another.

In an embodiment, a method is provided that includes controlling pluraltraction motors of a vehicle system to propel the vehicle system along aroute. The traction motors may be energized by a common power source andbe electrically parallel with respect to one another. The method alsoincludes receiving motor measurements that represent operatingparameters of the traction motors as the vehicle system propels alongthe route. The method also includes comparing the motor measurements toone another to determine whether the traction motors include differentmotor types.

In an embodiment, a control system is provided that includes ameasurement module configured to receive motor measurements thatrepresent operating parameters in plural traction motors of a commonvehicle system as the vehicle system propels along a route. The tractionmotors may be energized by a common power source and be electricallyparallel with respect to one another. The control system also includesan analysis module configured to calculate a performance relationship ofthe operating parameters for each of the traction motors based on themotor measurements. The analysis module is configured to determine thatthe traction motors include different motor types based on theperformance relationships for each of the traction motors.

In an embodiment, a method is provided that includes controlling pluraltraction motors of a vehicle system to propel the vehicle system along aroute. The traction motors include different motor types. The methodalso includes receiving motor measurements that represent operatingparameters of the traction motors as the vehicle system propels along aroute and calculating a performance relationship of the operatingparameters for each of the traction motors based on the motormeasurements. The method also includes determining that the tractionmotors include the motor types are different based on the performancerelationships for each of the traction motors.

In various aspects, in response to determining that the motor types ofthe traction motors are different or that at least one of the tractionmotors is different from a designated motor type, the systems andmethods set forth herein may be configured to at least one of (a) notifyan operator of the vehicle system of the at least one different motortype; (b) notify a remote monitoring station of the at least onedifferent motor type; (c) reduce tractive efforts of the at least onedifferent motor type; or (d) instruct a planning module to modify acurrent operating plan of the vehicle system based on the at least onedifferent motor type.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an embodiment of a vehicle systemtraveling along a route.

FIG. 2 is a schematic diagram of a propulsion-generating vehicle thatmay be used with the vehicle system of FIG. 1.

FIG. 3 illustrates torque-speed relationships for different types oftraction motors in accordance with an embodiment.

FIG. 4 illustrates current-speed relationships for different types oftraction motors in accordance with an embodiment.

FIG. 5 illustrates torque-speed relationships for different types oftraction motors that are controlled by a common inverter in accordancewith an embodiment.

FIG. 6 illustrates current-speed relationships for different types oftraction motors that are controlled by a common inverter in accordancewith an embodiment.

FIG. 7 illustrates torque-speed relationships for different types oftraction motors that are individually controlled by separate invertersin accordance with an embodiment.

FIG. 8 illustrates current-speed relationships for different types oftraction motors that are individually controlled by separate invertersin accordance with an embodiment.

FIG. 9 is a flowchart illustrating a method in accordance with anembodiment.

DETAILED DESCRIPTION

Embodiments of the inventive subject matter described herein includemethods and systems for determining that one or more fraction motors ofa vehicle system are unsuitable for the desired operation of the vehiclesystem or are not the same type as the other traction motors. Suchvehicle systems may include at least one propulsion-generating vehiclehaving plural fraction motors for generating tractive efforts of thevehicle system. In some cases, traction motors may also be used asgenerators during braking efforts. During operation of the vehiclesystem, motor measurements may be obtained that represent operatingparameters of the traction motors. The operating parameters relate tomotor performance. Non-limiting examples of operating parameters for atraction motor that may be utilized by embodiments described hereininclude a motor speed (e.g., rotation rate of the rotor of the tractionmotor), a motor slip, a wheel speed, a wheel creep, an excitationfrequency of the current that is supplied to the traction motor, avoltage supplied to the traction motor, a current supplied to thefraction motor, a motor current within a rotor of the traction motor(e.g., induced current), a torque of the traction motor, a horsepower ofthe traction motor, diameters of the axles or wheels coupled to thetraction motor, an impedance of the traction motor, and a reactance ofthe traction motor.

The motor measurements may be values of the operating parameters and maybe detected directly from the vehicle system or calculated based onother measurements. For example, torque and horsepower may be calculatedin different manners from a variety of measurements. The motormeasurements associated with a first traction motor may also be detectedby deactivating the first traction motor and measuring a change inperformance by other traction motors of the vehicle system. The changein performance of the other traction motors may be indicative of themotor performance of the first traction motor.

Based on these motor measurements, systems and methods set forth hereinmay determine that one or more of the traction motors is improper orincorrect for the desired operation of the vehicle system or that agroup of traction motors are mismatched. Embodiments may make thisdetermination by comparing the motor measurements to one or moreexpected measurements or metrics. The motor measurements that thedetermination is based on may be a single type of motor measurement(e.g., excitation frequency) or multiple types of motor measurements(e.g., excitation frequency and torque). It is understood that a varietyof types of measurements may be used, such as power measurements, heatmeasurements, tractive effort measurements, voltage and currentmeasurements, acceleration versus effort measurements, and the like.

The expected measurements or metrics may correspond to a designatedmotor type. More specifically, the expected measurement may representthe motor measurement that should be received if the motor-of-interest(e.g., one or more of the traction motors of the vehicle system) was ofthe designated motor type. The expected measurement may be a function ofthe operating conditions that the traction motors are currentlyoperating within. For instance, the expected measurement may be afunction of at least one of the excitation frequency, load of thevehicle system, an apportioned load for the motor-of-interest, operatingtemperature of the traction motor, other operating parameters describedherein, or external factors, such as weather conditions or a frictioncoefficient of the route. The expected measurement may be a range ofvalues, a baseline value, or a threshold value. In some cases, theexpected measurement or metric may be a performance relationship (e.g.,function) of multiple operating parameters. For example, a relationshipbetween motor speed and torque or between motor speed and current may bedetermined. In such instances, the expected metric may be a shape thatcorresponds to a portion of a relationship curve between the operatingparameters, which is described in greater detail below.

Embodiments may also determine that one or more of the traction motorsis unsuitable or does not match the other traction motors by comparingthe motor measurements of one traction motor to the motor measurementsof the other traction motors. As a specific example, traction motors ona common truck or propulsion-generating vehicle may be energized by acommon power source (e.g., inverter) and receive the same excitationfrequency. In this case, the motor measurements may be expected to beapproximately equal to each other. After comparing the motormeasurements of the different traction motors, it may be determined thatone of the traction motors is operating in a significantly differentmanner such that there is a high confidence that the traction motor is adifferent type of motor than the other traction motors. For instance,traction motors of the same type may have motor measurements that arewithin a designated range or percentage of each other.

Traction motors that have unexpected motor measurements may beidentified as unsuitable traction motors for the designated operation.In some embodiments, traction motors may be identified or labeled asbeing mismatched. For example, if one or more of the motor types of thetraction motors is incorrect or is not the expected motor type, thetraction motors may be mismatched. In response to detecting theunsuitable or mismatched traction motor(s), embodiments may, forexample, modify operation of the vehicle system, generate a plan forhaving the unsuitable traction motor replaced, and/or notify an operatoror control system so that the operator or control system is aware or sothat the operator or control system initiates a designated action foraddressing the unsuitable motor(s). In some embodiments, operation ofthe vehicle system may be modified by cutting out or disconnecting theunsuitable fraction motor (e.g., disconnecting contactors that supplypower to the traction motors). The operation may also be modified byreducing operation of the unsuitable traction motor (e.g., reducingtorque and/or motor speed). Operation of the vehicle system may also bemodified by changing an operating point, such as decreasing orincreasing flux.

In some embodiments, one or more of the propulsion-generating vehiclesmay include powered wheelsets. Each of the wheelsets may have a wheelthat is coupled to an axle that is driven by a traction motor.Propulsion systems (or the corresponding propulsion-generating vehicle)that have multiple wheelsets controlled by a common inverter may bereferred to as per-truck systems (or per-truck vehicles). Propulsionsystems (or the corresponding propulsion-generating vehicle) that havemultiple wheelsets in which each wheelset is controlled by a separateinverter may be referred to as per-axle systems (or per-axle vehicles).

Propulsion systems may be configured to operate with a designated typeof traction motor. Traction motors of a particular motor type may beconfigured to have designated motor characteristics. More specifically,the various components of the traction motors, such as the structure ofthe stator, rotor, and windings, may be designed to achieve a designatedperformance. A composition of the stator, rotor, and windings, such as aratio of copper to iron, may also be configured to achieve a designatedperformance.

In certain embodiments, the traction motors of different types may havedifferent performance relationships among the operating parameters. Insome embodiments, the different performance relationships may beidentified upon analysis of the traction motors during operation. Forinstance, different motor types may have different torque-speedfunctions, current-speed functions, torque-slip functions, current-slipfunctions, and the like. Each of these functions may have identifiablefeatures or portions that are indicative of the motor type. As aspecific example, the above functions may be substantially linear whenthe motor speed is proximate to the synchronous speed of the tractionmotor. The slope of these linear portions, however, may differ based onthe motor type.

Although traction motors of the same type may have variations inperformance due to manufacturing tolerances and operational wear of thetraction motors, such variations may be insubstantial compared to thedifferences in performance of different types of traction motors. Forinstance, traction motors may be designed to provide a designated motorspeed as a function of expected load or motor slip or may be designed toprovide a designated starting torque, pull-up torque, breakdown torque,or full-load torque. As such, traction motors of a motor type that isdesigned for particular applications may provide measurements or haveperformance relationships that distinguish this motor type from othermotor types. By way of example, locomotives that frequently travel alongsteep routes may have traction motors that are configured differentlythan locomotives that frequently travel along flat routes. Locomotivesconfigured to carry large loads (e.g., coal) may be configured forhigh-weight, low-speed applications. Locomotives configured for lighterloads (e.g., passengers) may be configured for low-weight, high-speedapplications.

As another example, per-axle systems may be configured to have tractionmotors with low resistance rotors and per-truck systems may beconfigured to have high resistance rotors. Per-axle vehicles include theAC Series and Evolution Series developed by General Electric. Per-truckvehicles include the Electro-Motive Diesel (EMD) developed by GeneralMotors. Embodiments set forth herein may be configured to identifyfraction motors having low resistance rotors among fraction motorshaving high resistance rotors and vice versa. For example, a torque-slipcharacteristic may be calculated for each traction motor duringoperation of a vehicle system. The traction motor(s) configured forper-axle systems will have a different torque-slip characteristic forthe traction motor(s) configured for per-truck systems.

A vehicle system may include multiple propulsion-generating vehicles. Insuch instances, the multiple propulsion-generating vehicles may bearranged to form a single vehicle consist or a plurality of vehicleconsists. In some embodiments, the propulsion-generating vehicles of asingle vehicle consist are configured to communicate with each other tocoordinate tractive efforts and/or braking efforts. Vehicle systems mayalso include multiple vehicle consists. In some cases, the vehicleconsists may communicate with one another. As one specific example, atrain may include first, second, and third locomotive consists, whereineach of the locomotive consists includes two locomotives. The locomotiveconsists may receive instructions from a control system for controllingoperations of the two locomotives.

In some embodiments, the motor measurements are acquired during normaloperation of the vehicle system. For example, the motor measurements maybe acquired without deviating from an operating plan or withoutdeviating from inputs or instructions from an operator (e.g., engineer).An operating plan, which may also be referred to as a trip plan ormission plan, may include instructions for controlling thepropulsion-generating vehicles to provide designated tractive effortsand/or designated braking efforts for predetermined portions of a trip.The instructions may be expressed as a function of time and/or distanceof a trip along a route. In some embodiments, upon detecting that thetraction motors are mismatched or that one or more fraction motors areunsuitable for the desired operation, the systems and methods describedherein may modify the operating plan based on the unsuitable tractionmotor. For example, the operating plan may instruct the propulsionsystem that includes the unsuitable fraction motor to reduce tractiveefforts by half

FIG. 1 is a schematic diagram of a vehicle system 100 formed inaccordance with an embodiment. In the illustrated embodiment, thevehicle system 100 is a rail vehicle system. While the descriptionherein refers specifically to rail vehicles, such as locomotives, notall embodiments are so limited. The inventive subject matter describedherein may be used in connection with one or more other vehicles orvehicle systems, such as automobiles for traveling along roads,off-highway vehicles, construction or farming equipment, and marinevessels.

As shown, the vehicle system 100 is traveling along a portion of a routeor track 102. The vehicle system 100 includes a plurality of discretevehicles. As used herein, “discrete” vehicles are separate and distinctvehicles that are capable of being removably coupled to and part of alarger vehicle system. The vehicle system 100 may be a rail vehiclesystem that includes at least one propulsion-generating vehicle (e.g.,locomotive) and, optionally, at least one non-powered vehicle (e.g.,rail car or passenger car) that are linked to one another.

In the illustrated embodiment, the vehicle system 100 includespropulsion-generating vehicles 104 and 105 and non-powered vehicles 106and 107 that are mechanically linked to one another and are configuredto travel as a group along the track 102. The terms “powered” or“propulsion-generating” refer to the capability of a vehicle to propelitself and not whether the vehicle receives or generates energy for oneor more other purposes. For example, the non-powered vehicles 106, 107may receive electric current to power one or more loads disposed onboardthe non-powered vehicles 106, 107 (e.g., air conditioning, lighting,etc.).

In FIG. 1, the propulsion-generating vehicle 104 may be considered aprincipal or lead vehicle of a vehicle consist 110, and thepropulsion-generating vehicle 105 may be considered a remote vehicle ofthe vehicle consist 110. A propulsion-generating vehicle that controlsone or more other propulsion-generating vehicles may be referred to asthe “principal” or “lead” propulsion-generating vehicle, andpropulsion-generating vehicles that are controlled by anotherpropulsion-generating vehicle may be referred to as the “remote”propulsion-generating vehicles. The principal propulsion-generatingvehicle may or may not lead other vehicles along the route. Theplurality of propulsion-generating vehicles 104, 105 in the singlevehicle consist 110 are configured to operate as a single movingapparatus. For example, the multiple propulsion-generating vehicles 104,105 may coordinate tractive efforts and/or braking efforts to propel thevehicle system 100 along the track 102.

A vehicle system may be or include a single vehicle consist or include aplurality of vehicle consists that are directly or indirectly coupled toanother. For example, the vehicle system 100 includes a second vehicleconsist 111 that is coupled to the vehicle consist 110. When a vehiclesystem includes multiple vehicle consists, the vehicle consists may bereferred to as sub-consists. If the vehicle system includes multiplevehicle consists, the vehicle consists may be configured to operate as asingle moving apparatus. For example, the multiple vehicle sub-consistsmay be controlled by a master computing system that coordinates tractiveand/or braking efforts among the sub-consists to control operation ofthe vehicle system as a whole. The master control system may also beconfigured to acquire motor measurements as described herein.

Also shown in FIG. 1, the vehicle system 100 may communicate with anoff-board control system 116 that can be disposed off-board (e.g.,outside) of the vehicle system 100. For example, the control system 116may be disposed at a central dispatch office 115 for a railroad company.The control system 116 can generate and communicate various operatingplans and/or communicate information regarding track conditions. Thecontrol system 116 may also include one or more modules for receivingand analyzing the motor measurements acquired by the vehicle system 100.The control system 116 can include a wireless antenna 118 (andassociated transceiving equipment), such as a radio frequency (RF) orcellular antenna, that wirelessly transmits signals to the vehiclesystem 100. The vehicle system 100 may also include a wireless antenna120 (and associated transceiving equipment). In some embodiments, thecontrol system 116 may be configured to determine that one or moretraction motors are unsuitable for the desired operation of the vehiclesystem 100 or that the traction motors are mismatched. For example, thecontrol system 116 may include similar modules as the control system 206(shown in FIG. 2) described below.

FIG. 2 is a schematic diagram of a propulsion-generating vehicle 200,which may be part of a rail vehicle system 200, such as the vehiclesystem 100 (FIG. 1). The propulsion-generating vehicle 200 mayconstitute or be part of a vehicle consist that may or may not becoupled with other vehicle consist(s) (not shown) in the rail vehiclesystem. As shown, the propulsion-generating vehicle 200 includes acontrol system 206 that is configured to control operation of thepropulsion-generating vehicle 200 and, optionally, otherpropulsion-generating vehicles of the vehicle system that includes thepropulsion-generating vehicle 200. Alternatively, the control system 206may be distributed between the propulsion-generating vehicles. Forembodiments that include multiple vehicle consists, the control system206 may be configured to control operation of other vehicle consists.

The propulsion system 220 can include a variable speed prime mover orengine 224 that is mechanically coupled to a rotor of a dynamo electricmachine. In the illustrated embodiment, the dynamo electric machine isan alternator 226 and, in particular, a 3-phase alternating current (AC)synchronous alternator. The 3-phase voltages generated by the alternator226 are supplied to input terminals of a power rectifier bridge 228. Therectifier bridge 228 may transform or modify the AC power from thealternator 226 into direct current (DC) power. The power rectifierbridge 228 has output terminals that supply the DC power to a DC link orbus 230. Although the propulsion system 220 is described as being anAC-type propulsion system that is powered by diesel, it is understoodthat embodiments set forth herein may also be implemented withpropulsion systems that are at least partially powered by electricity(e.g., batteries, catenary system, and the like).

As shown, the DC link 230 is electrically connected to inverters 232,234. The inverters 232, 234 are configured to convert (e.g., invert) theDC power into AC power at a controlled frequency for powering tractionmotors 241-244. The inverters 232, 234 may employ high power gateturn-off devices which switch in and out of conduction in response togating signals from the control system 206 (or the vehicle-controlmodule 210) so as to invert the DC voltage on the DC link 230 to acontrolled frequency AC voltage.

The traction motors 241, 242 are electrically connected to and poweredby the inverter 232, and the traction motors 243, 244 are electricallyconnected to and powered by the inverter 234. The traction motors 241,242 are electrically parallel to each other, and the traction motors243, 244 are electrically parallel to each other. Electrically paralleltraction motors may receive the same excitation frequency from thecorresponding inverter. In alternative embodiments, the traction motors241, 242 and/or the traction motors 243, 244 may be in series. Otherembodiments may include a combination of traction motors that are inseries and in parallel. In some embodiments, the traction motors 241-244are adjustable speed AC traction motors (e.g., induction motors). Alsoshown, the motors 241-244 are operably coupled to axles 251-254,respectively, that are each coupled to wheels 271-274. The motors241-244, the axles 251-254, and the wheels 271-274 may constituterespective axle wheelsets 261-264. For example, the traction motor 241,the axle 251, and a pair of wheels 271 may constitute the wheelset 261,which is configured to generate a tractive effort for propelling thepropulsion-generating vehicle 200 and, hence, the rail vehicle system200. Each of the axle wheelsets 261-264 may be selectively controlledthe control system 206 to provide a designated tractive effort orbraking effort.

In the illustrated embodiment, the propulsion system 220 is a per-trucksystem having two separate trucks 216, 218. For example, each of theinverters 232, 234 controls a pair of traction motors that areelectrically parallel. In other embodiments, the inverters 232, 234 maycontrol more than two traction motors (e.g., three or four). Theinverter 232 and the traction motors 241, 242 may be part of orconstitute a first truck 216. The inverter 234 and the fraction motors243, 244 may be part of or constitute a second truck 218. Each of thetrucks 216, 218 may be secured to a frame of the propulsion-generatingvehicle 200.

In other embodiments, the propulsion system 220 may be a per-axle systemin which each of the traction motors 241-244 is controlled by a singleinverter that is configured to exclusively control the respectivetraction motor. Such embodiments may enable individual control of thetraction motors.

Although the illustrated embodiment shows a 4-axle propulsion system, itis understood that the inventive subject matter described herein is notlimited to 4-axle systems and is equally applicable to other systems.For example, the propulsion system 220 may be a 6-axle locomotive withtwo inverters that are each connected for powering three tractionmotors. Alternatively, the propulsion system 220 may be a 6-axlelocomotive with six inverters each connected for powering a respectiveone of six traction motors.

In the illustrated embodiment, the propulsion-generating vehicle 200 andan adjacent rail vehicle 204 are directly connected by a mechanicalcoupler 266. The rail vehicle 204 may be another propulsion-generatingvehicle or may be a non-powered vehicle. The mechanical coupler 266 mayallow some tolerance or slack such that the propulsion-generatingvehicle 200 and the rail vehicle 204 are permitted to move a limiteddistance toward each other or away from each other. The coupler 266 maypermit a communication cable 265 to extend between and communicativelycouple the vehicles 200, 204.

The rail vehicle system 200 travels along a route 208, such as a trackhaving one or more rails. The propulsion-generating vehicle 200facilitates driving the vehicle system 200 using the wheelsets of thevehicle. For example, the fraction motors 241-244 deliver torque to thewheels 271-274, which exert tangential force (e.g., tractive effort)along the route 208, thereby propelling the rail vehicle system 200along the route 208. The tractive effort developed at each wheel of thepropulsion-generating vehicle 200 is proportional to a normal force 280acting on the respective wheel.

For a dynamic braking mode, the traction motors 241-244 are reconfigured(via power switching devices (not shown)) so that the fraction motors241-244 operate as generators. So configured, the traction motors241-244 generate electric energy which has the effect of slowing thepropulsion-generating vehicle 200. In some cases, energy generated in adynamic braking mode may be transferred to resistance grids (not shown)that are coupled to the propulsion-generating vehicle 200. The dynamicbraking energy may be converted to heat and dissipated from thepropulsion-generating vehicle 200 through the grids. In otherembodiments, the dynamic braking energy may be stored (e.g., batteries)by the propulsion-generating vehicle 200.

Also shown in FIG. 2, the rail vehicle system 200 may include a numberof detection devices 291-295. The detection devices 291-295 of thecontrol system 206 may be located at various points in thepropulsion-generating system 200. For example, the detection devices293, 294 are coupled to the inverters 232, 234, respectively. Thedetection devices 291, 292 are coupled to each of the traction motors241-244. The detection devices 291-295 are configured to monitor one ormore operating parameters of the traction motors 241-245. Morespecifically, the detection devices 291-295 may obtain measurementsrelating to the operating parameters to determine a performancerelationship of the fraction motors 241-245. In some embodiments, thedetection devices 291-295 are configured to detect a motor measurementor other measurements that may be used to calculate a motor measurement.Motor measurements may include excitation frequency of the current, asupply voltage, a motor current (e.g., induced current), a torque orhorsepower, a motor speed or rotation rate of the rotor, axle or wheeldiameters of the traction motor, a motor slip, impedance of the tractionmotor, or reactance of the traction motor. In some embodiments, thedetection devices 291-295 may also be configured to detect torsionalvibrations, vehicle speed (e.g., ground speed), wheel strain, axlestrain, or dog-bone strain.

The detection device 295 may be operably connected to the mechanicalcoupler 266 and configured to detect stresses or forces sustained at themechanical coupler 266. In some embodiments, the data obtained by thedetection device 295 may be used to calculate the measurements used todetermine torque or horsepower. In some embodiments, the detectiondevices may include a radar system (e.g., Doppler radar gun or othertype of radar system) or a Global Positioning System (GPS) system thatis used to obtain the data representative of the speed at which thepropulsion-generating vehicle 200 moves along the route 208.

The control system 206 is configured to control at least some operationsof the propulsion-generating vehicle 200. In some embodiments, thecontrol system 206 may also control operations of other vehicles. Forinstance, the control system 206 may be a master control systemconfigured to control operation of multiple vehicles within a consist orto control operation of multiple consists. As shown, the control system206 includes a plurality of modules 281-284. The control system 206 andthe corresponding modules 281-284 may be controllers, processors, orother logic-based devices that perform operations based on one or moresets of instructions (e.g., software). In some cases, the differentmodules of the control system 206 are part of the same logic-baseddevice or, alternatively, are distributed within multiple logic-baseddevices. The instructions on which the control system 206 operates maybe stored on a tangible and non-transitory (e.g., not a transientsignal) computer readable storage medium, such as a memory. The memorymay include one or more computer hard drives, flash drives, RAM, ROM,EEPROM, and the like. Alternatively, one or more of the sets ofinstructions that direct operations of the control system 206 may behard-wired into the logic of the control system 206, such as by beinghard-wired logic formed in the hardware of the control system 206.

The vehicle-control module 281 is configured to control tractive and/orbraking operations of the propulsion-generating vehicle 200. To thisend, the vehicle-control module 281 is configured to communicate with apropulsion system 220 and a braking system (not shown). Thevehicle-control module 281 may instruct (e.g., communicate signals toone or more components of the propulsion system 220) to increase ordecrease power, tractive effort, etc. For example, the instructions maybe in accordance with one or more operating plans that designatetractive operations (e.g., notch or throttle settings) and brakingoperations to be implemented by the propulsion-generating vehicle 200.In an embodiment, the vehicle-control module 281 may autonomouslycontrol operations of the propulsion-generating vehicle 200 according tothe operating plan.

The measurement module 282 is configured to receive the motormeasurements or other data that represent operating parameters of thetraction motors 241-244 as the vehicle 200 travels along the route 208.In some embodiments, the measurement module 282 may analyze themeasurements received from detection devices, such as the detectiondevices 291-295, and/or data to determine that the measurements or datais sufficient or trustworthy. The measurement module 212 may package themeasurement or data in predetermined format so that the control system206 and other modules 282-284 may recognize the measurements. In somecases, the measurement module 212 may execute preliminary processingsteps. For example, the measurement module 212 may obtain data from thedetection devices 291-295 and calculate the motor measurements that willbe used to determine whether the traction motors are suitable or whetherthe traction motors are mismatched.

In some cases, the measurement module 212 may designate the data ormotor measurements as operating conditions. The operating conditions maybe used to identify an expected measurement for comparing to the motormeasurements. For example, the operating conditions may be an excitationfrequency and a load of the propulsion-generating vehicle 200. With thisinformation, the measurement module 212 may use one or more databases orfunctions to identify an expected measurement of a designated motor typeor types. In some embodiments, the measurement module 212 may also beconfigured to calculate a performance relationship among differentoperating parameters. The performance relationships may be functionsthat represent a relationship between different operating parameters,such as motor speed, motor current, motor slip, torque, or horsepower.Such performance relationships are illustrated in FIGS. 3-8.

In some embodiments, the measurement module 212 may communicate themeasurements or data relating to the measurements to a transmitter 296.The transmitter 296 may be configured to communicate the motormeasurements and/or the operating conditions to, for example, thecontrol system 116. As described herein, the control system 116 may beconfigured to perform the same operations as the control system 206 fordetermining whether the traction motors are not suitable or aremismatched.

The analysis module 283 is configured to analyze the motor measurementsto determine whether one or more of the traction motors is not suitablefor the propulsion-generating vehicle 200 or for the vehicle system thatincludes the propulsion-generating vehicle 200. For example, theanalysis module 283 may compare the motor measurements to an expectedmeasurement, may compare the motor measurements of the differenttraction motors, or may compare the calculated performance relationshipsof the traction motors. Such operations are described in greater detailbelow with respect to the method 500.

The planning module 284 is configured to generate an operating plan forcontrolling operations of the propulsion-generating vehicle 200 or thevehicle system that includes the propulsion-generating vehicle 200. Forexample, in response to determining that one or more the traction motorsis an unsuitable type of motor or are not like other traction motors,the planning module 284 may modify a currently-implemented or existingoperating plan. The operating plan may be configured to improve theperformance of the propulsion-generating vehicle 200 and/or to limit theperformance of the propulsion-generating vehicle 200 to prevent damageor reduce the likelihood of wear and damage.

The operating plan may include instructions for controlling tractiveand/or braking efforts of the vehicle. The instructions may be expressedas a function of time and/or distance of a trip along a route. In someembodiments, travel according to the instructions of the operating planmay cause the vehicle to reduce a stress on a fraction motor relative tothe stress that would be sustained by the traction motor if theoperating plan were not generated. For example, the operating plan mayinstruct the vehicle to reduce the excitation frequency to a tractionmotor, to intermittently drive the traction motor, or to disable thetraction motor altogether. If the motor-of-interest is a member of a setof traction motors of a per-truck system, the operation plan mayinstruct the vehicle to reduce the excitation frequency of the set oftraction motors, to intermittently drive the set of traction motors, orto disable the set of traction motors. The vehicle may be autonomouslycontrolled according to the operating plan or the instructions of theoperating plan may be presented to an operator of the vehicle so thatthe operator can manually control the vehicle according to the operatingplan (also referred to herein as a “coaching mode” of the vehicle).

The planning module 284 may be configured to use at least one of vehicledata or route data (or a route database) to generate the operating plan.The vehicle data may include information on the characteristics of thevehicle. For example, when the vehicle is a rail vehicle, the vehicledata may include a number of rail cars, number of locomotives,information relating to an individual locomotive or a consist oflocomotives (e.g., model or type of locomotive, weight, powerdescription, performance of locomotive traction transmission,consumption of engine fuel as a function of output power (or fuelefficiency), cooling characteristics), load of a rail vehicle witheffective drag coefficients, vehicle-handling rules (e.g., tractiveeffort ramp rates, maximum braking effort ramp rates), content of railcars, lower and/or upper limits on power (throttle) settings, etc. Thevehicle data may also include part data regarding the traction motors.For example, if the traction motors are determined to be designatedmotor types, the planning module 284 may use historical informationregarding such motor types in generating the operating plan.

Route data may include information on the route, such as informationrelating to the geography or topography of various segments along theroute (e.g., effective track grade and curvature), speed limits fordesignated segments of a route, maximum cumulative and/or instantaneousemissions for a designated segment of the route, locations ofintersections (e.g., railroad crossings), locations of certain trackfeatures (e.g., crests, sags, curves, and super-elevations), locationsof mileposts, and locations of grade changes, sidings, depot yards, andfuel stations. The route data, where appropriate, may be a function ofdistance or correspond to a designated distance of the route. In oneembodiment, the planning module 284 includes a software application orsystem such as the Trip Optimizer™ system developed by General ElectricCompany.

FIGS. 3-8 include plots or graphs illustrating performance relationshipsof traction motors. In the illustrated embodiment, the traction motorsare induction motors. Similar performance relationships may bedetermined, however, for other types of traction motors, such asdirect-current (DC) motors or alternating current (AC) synchronousmotors. In each of the plots, the vertical axis (y-axis) representstorque or motor current and the horizontal axis (x-axis) representsmotor speed. Motor speed may be the number of times the rotor rotates ina designated period of time. In FIGS. 3-8, the motor speed is in unitsof frequency (e.g., Hz), the torque is in units of ft-lbs, and thecurrent is in units of amperes or amps. It is understood, however, thatthe performance relationships may be calculated with other units.Moreover, similar performance relationships may be calculated withrelated operating parameters. For example, tractive effort may besubstituted for torque and motor slip may be substituted for motorspeed. For embodiments in which the traction motors are inductionmotors, the motor current may be deduced or calculated based on theincoming current, which may be detected by a sensor in some embodiments.Torque may be calculated based on one or more measurements.

FIG. 3 is a plot representing torque-speed relationships of twodifferent traction motors. Torque is represented by the vertical axisand the motor speed is represented by the horizontal axis. A curve 301represents the torque-speed relationship of a low-slip traction motor,which may be used by per-axle systems, and a curve 311 represents thetorque-speed relationship of a high-slip fraction motor, which may beused by per-truck systems. As described above, the differences in thecurves 301, 311 may be based on differences in the structures and/orcompositions of the components of the traction motors. In some cases,differences may also exist between traction motors of the same type.Such differences may be based on manufacturing tolerances and/oroperating temperatures of the traction motors.

In some embodiments, the operating temperatures of the traction motorsmay be accounted for in determining whether the traction motors aremismatched. For instance, the shapes of the curves 301, 311 may befunctions of the operating temperature of the corresponding tractionmotor. Performance relationships may be based on the operatingtemperature of the traction motor. As such, fraction motors of the sametype may have portions of the curves 301, 311 with different slopes dueto the operating temperatures of the traction motors being different.For example, in some cases, as the operating temperature of the tractionmotor increases, a substantially linear portion of the curve may becomeshallower. Accordingly, embodiments may be configured to compensate fordifferent operating temperatures when determining whether differenttraction motors are of the same or different types.

Embodiments set forth herein may be configured to determine whether oneor more fraction motors are unsuitable in the vehicle system and/orwhether the traction motors are mismatched by determining performancerelationships of the traction motors (e.g., one or more portions orpoints of the curves 301, 311) and comparing the determined performancerelationships to designated relationships (e.g., expected or knownperformance relationships). As one example only, embodiments maycalculate a linear portion of the curves (described in greater detailbelow) to determine the slope of the linear portion and compare thecalculated slope to expected or known slope values for high-slip andlow-slip motors. However, this is only one specific example and it isunderstood that embodiments are not limited to calculating linearportions of the performance relationships.

Furthermore, it is noted that the curves in FIG. 3 and the curves inother figures are for illustration only. For instance, other embodimentsmay use different units or may detect different values than those shownin the curves. Moreover, in other embodiments, the relationships betweenthe values may differ. Accordingly, the shapes of the curves in FIG. 3are provided only as examples.

As shown, each of the curves 301, 311 intersects the horizontal axis at320, which represents a synchronous speed (or frequency) of the tractionmotors. Synchronous speed of a fraction motor is equal to a speed of therotating magnetic field that is generated by the stator. The synchronousspeed is dependent upon the excitation frequency of the input current.During a motoring stage of the traction motor, torque is generated bythe traction motor to move the axle coupled to the traction motor. Themotor speed at the motoring stage is less than the synchronous speed inorder to generate the torque. More specifically, when the rotor of thetraction motor rotates at a motor speed that is less than thesynchronous speed, current is induced within the rotor which generates aforce for moving the axle. However, when the rotor rotates at thesynchronous speed, the current induced within the rotor is at a minimumand no torque is generated. For example, each of the traction motorsgenerates zero torque at the synchronous speed 320.

When the vehicle system achieves a designated cruising speed (e.g.,speed of the vehicle) during a motoring stage, it is generally desirablefor the motor speed to be greater than the motor speed that correlatesto a maximum torque (also referred to as a breakdown torque). Themaximum torque of the low-slip traction motor is indicated at 302, andthe maximum torque of the high-slip traction motor is indicated at 312.The motoring stage for the low-slip traction motor is indicated at 303and, in FIG. 3, correlates to a motor speed between about 59.2 rpms and61 rpms. The motoring stage for the high-slip traction motor isindicated at 313 and correlates to a motor speed between about 57.2 rpmsand 61 rpms. As shown, the motoring stages 303, 313 of the low-slip andhigh-slip traction motors, respectively, have different ranges of motorspeeds.

Also shown, the curves 301, 311 include a generally linear portion inthe motoring stages 303, 313. Slopes of the linear portions, however, atthe respective motoring stages 303, 313 are different. For example, thecurve 301 along the motoring stage 303 is steeper than the curve 311along the motoring stage 313 (or the curve 311 is shallower than thecurve 301). The low-slip traction motor is more sensitive to changes inmotor speed in which a small change in motor speed results in arelatively large change in torque. The high-slip traction motor, on theother hand, is less sensitive to changes in motor speed. In the exampleshown in FIG. 3, when the motor speed reduces from the synchronousspeed, the low-slip traction motor increases torque about twice as fastas the high-slip traction motor.

It is noted that various types of fraction motors have similar linearrelationships between the torque and the motor speed during the motoringstage. The slopes of the linear portions, however, can be differentamong different types of traction motors. As such, the slopes of thetorque-speed curves during the motoring stages may be used to at leastone of determine that the traction motors are different or identify atype of traction motor. For example, during operation of the tractionmotors in the motoring stages 303, 313, the maximum torques 302, 312 maybe identified. The slopes of the linear portions of the curves 301, 311may be calculated using the synchronous speed 320 as one data point andthe maximum torques 302, 312 as other data points. With respect to theembodiment of FIG. 3, the high-slip traction motor may have a constant Kfor the motoring stage 313 that is equal to −X, and the low-sliptraction motor may have a constant K for the motoring stage 303 that isequal to −2X. To determine whether the traction motors are differenttypes, the values of the constant K may be compared to each other orcompared to expected values within a database or look-up table.

As noted herein, embodiments are not limited to calculating linearportions of the performance relationships. Instead, embodiments maydetermine any relationship metric (e.g., point, shape, slope, and thelike) of the performance relationship and compare the determinedrelationship metric to an expected or known metric. The relationshipmetric and the expected metric may correspond to, for example,designated shapes of a curve, slopes between two points of thecorresponding curve, values at a designated point of the curve (e.g.,maximum value in the curve), or ranges of values between two points ofthe curve. In some embodiments, the expected metric may be a thresholdvalue, a baseline value, and the like. If the relationship metric isabove a threshold or below a baseline, the traction motor correspondingto the relationship metric may be determined to be unsuitable ormismatched.

FIG. 4 is a plot representing current-speed relationships of thelow-slip and high-slip traction motors of FIG. 3. A curve 331 representsthe current-speed relationship of a low-slip traction motor, and a curve341 represents the current-speed relationship of a high-slip tractionmotor. Similar to the torque of the low-slip and high-slip tractionmotors, the differences in the curves 331, 341 may be based ondifferences in the structures and/or compositions of the components ofthe traction motors.

The current-speed relationships shown in FIG. 4 may also be used todetermine that the traction motors are different types. Similar to thecurves 301, 311 of FIG. 3, the curves 331, 341 of FIG. 4 havesubstantially linear portions during the motoring stages 303, 313,respectively. Each of the curves reaches a minimum at 352, whichrepresents an amount of current at the synchronous speed. Duringoperation of the traction motors in the motoring stage, a plurality ofdata points of the current may be determined. The slopes of the linearportions of the curves 331, 340 may be calculated using the data pointsalong of the curves 331, 340 and the minimum 352 as another data point.

FIGS. 5 and 6 illustrate performance relationships of three tractionmotors in which the traction motors are electrically parallel andtherefore supplied with the same excitation frequency. The excitationfrequency may be supplied by a common inverter. However, in otherembodiments, the traction motors may be in series or a combination oftraction motors may be in parallel and in series. In such instances, theperformance relationships may be different than those shown in thefigures.

FIG. 5 shows a plot of the torque-speed relationships, and FIG. 6 showsa plot of the current-speed relationships. With respect to FIG. 5, acurve 401 represents a torque-speed relationship of a low-slip fractionmotor. A curve 411 represents identical torque-speed relationships oftwo high-slip traction motors. Only one curve 411 is shown because thecurves of the two high-slip traction motors are overlapping aftercompensation for operating temperature. With respect to FIG. 6, a curve421 represents a current-speed relationship of the low-slip fractionmotor. A curve 431 represents identical current-speed relationships ofthe two high-slip traction motors. Again, only one curve 421 is shownbecause the curves of the two high-slip traction motors are overlapping.

During operation of the vehicle system having the low-slip tractionmotor and the high-slip traction motors, a vehicle-control module, suchas the vehicle-control module 281, may control the inverter to achieve adesignated total tractive. For example, the vehicle-control module 281may adjust an excitation frequency of the inverter until a totaltractive effort of 9000 ft-lbs. In FIG. 5, the excitation frequency is64 Hz. When the motor speed is 60 Hz as shown, the vehicle system mayachieve the total tractive effort of 9000 ft-lbs.

However, maintaining the motor speed at 60 Hz may have undesired effectson the low-slip fraction motor. For example, for the embodiment shown inFIGS. 5 and 6, the current of the low-slip traction motor is at 3500 Aand the current of the high-slip traction motors is about 2500 A. Thus,for less tractive effort, the low-slip tractive motor draws asignificantly larger current than the high-slip tractive effort. Forper-truck embodiments, if a first traction motor has a torquemeasurement that exceeds the torque measurement of a second tractionmotor, but the current measurement of the first traction motor is lessthan the current measurement of the second traction motor, then thefirst traction motor may be designated as not matching the othertraction motors or as being an unsuitable type of motor.

FIGS. 7 and 8 illustrate performance relationships of three tractionmotors in which the fraction motors are individually controlled byseparate inverters. As such, the excitation frequency and, hence, thesynchronous speed of the fraction motors may vary. With respect to FIG.7, a curve 451 represents identical torque-speed relationships of twolow-slip traction motors. A curve 461 represents a torque-speedrelationship of a high-slip traction motor. With respect to FIG. 8, acurve 471 represents identical torque-speed relationships of twolow-slip traction motors. A curve 481 represents a torque-speedrelationship of a high-slip traction motor. As shown in FIGS. 7 and 8,the curves 451, 461, 471, and 481 have different features orcharacteristics. As described below with respect to the method 500 (FIG.9), these features or characteristics may be used to determine that thelow-slip traction motor was incorrectly installed into the vehiclesystem.

In FIGS. 5-8, the performance relationships of traction motors of thesame type (e.g., high-slip or low-slip) have been shown as beingrepresented by identical curves. When one or more embodiments areimplemented, however, the performance relationships may not beidentical. For example, traction motors that are of the same type (e.g.,designed to provide the same motor performance) may have slightlydifferent performance relationships due to tolerances in themanufacturing process of the traction motors or due to operatingtemperatures of the traction motors. Furthermore, although tractionmotors may be of the same motor type, two traction motors may havedifferent lifetime experiences and, as such, may have sustained unequalamounts of wear. In addition to the traction motors, the wheels or axlesattached to the traction motors may have varying degrees of wear. Forexample, even if the wheel diameters of two wheels on a common truckdiffer only slightly (e.g., by 0.5-1.0%), the performance relationshipsof the two traction motors may be different. Nonetheless, in many cases,the performance relationships may have the same features orcharacteristics that distinguish one motor type of another. Thus, it isunderstood with the embodiments described herein that motor types may bedifferentiated even if the traction motors have different degrees ofwear and/or the axles and wheels attached to the traction motors mayhave different degrees of wear.

In some cases in which the motor types are different or when thetraction motors are of the same type but provide different performancesdue to wear or tolerances in the manufacture of the traction motors, anevent may occur in which a first traction motor is braking and a secondtraction motor is generating power. More specifically, due to theperformance differences, the first traction motor may have a positivetorque along the performance curve and the second traction motor mayhave a negative torque along the performance curve such that the secondtraction motor is generating power (e.g., through dynamic braking) Insuch instances, the first and traction motors work against each other.Even though each of the first and second traction motors may beeffectively providing some effort (e.g., tractive or braking efforts),the overall torque provided by the first and second traction motors maybe about zero. During these circumstances, it may be difficult to obtaina desired performance from the first and second traction motors and/orone or more of the traction motors may overheat. In addition to theabove, if the fraction motors are of different types, compensation fornon-motor characteristics, such as manufacturing tolerances oroperational differences (e.g., wheel diameter), may be furthercompromised, which can also lead to overheating or increased losses.

In some embodiments, the vehicle system may identify the different motortypes and control operation of the traction motors to avoid or reducethe number of times the traction motors work against each other. Forexample, the planning module 284 may generate operating plans thatreduce the number of times first and second traction motors work againsteach other and/or reduce the duration in which the first and secondtraction motors are working against each other.

FIG. 9 is a flow chart illustrating a method 500 in accordance with anembodiment. The method 500, for example, may employ structures oraspects of various embodiments (e.g., systems and/or methods) discussedherein. In various embodiments, certain steps (or operations) may beomitted or added, certain steps may be combined, certain steps may beperformed simultaneously, certain steps may be performed concurrently,certain steps may be split into multiple steps, certain steps may beperformed in a different order, or certain steps or series of steps maybe re-performed in an iterative fashion. The method 500 (or certainsteps thereof) may be implemented by one or more algorithms that areexecuted by logic-based devices to control hardware (e.g., propulsionsystem, control system, individual modules of the control system) toperform designated operations as described herein.

The method 500 includes controlling (at 502) plural traction motors of avehicle system to propel the vehicle system along a route. The fractionmotors may be part of the same truck, the same propulsion-generatingvehicle, or the same vehicle system, which may include multiplepropulsion-generating vehicles and, optionally, multiple vehicleconsists. In certain embodiments, the propulsion-generating vehicles areper-truck or per-axle vehicles. As used herein, controlling the pluraltraction motors to propel the vehicle system along a route includespropelling the vehicle system along a major route that isheavily-trafficked or along a route that is not heavily-trafficked, suchas tracks by a wayside station. More specifically, the vehicle systemmay be traveling at relatively slow vehicle speeds (e.g., less than 10miles per hour (mph) (or 16.1 kilometers per hour (kph)) or relativelyfast vehicle speeds (e.g., 50 mph or more (or 80.5 kph or more)) or at avehicle speed in between. In particular embodiments, at least some ofthe motor measurements may be acquired when the traction motors areoperating at respective motoring stages, such as when the motor speed isbetween the synchronous speed and a motor speed that corresponds to themaximum possible torque of the traction motor.

At 504, motor measurements may be received that represent operatingparameters of the traction motors. In some embodiments, the operatingparameters may relate directly to a performance or output of thetraction motor, such as torque, horsepower, tractive effort, motorcurrent, motor slip, or motor speed. The operating parameters may alsorelate directly to one or more inputs that cause the directly effect theperformance of the traction motor, such as a supply current, excitationfrequency, and supply voltage. Other operating parameters may bemonitored as well, such as wheel slip, axle and/or wheel diameters,thermal rise, impedance, reactance, etc.

The motor measurements may be compared (at 506) to an expectedmeasurement. In some embodiments, the comparing (at 506) may beperformed by the analysis module 283 (FIG. 2). The expected measurementsmay correspond to a designated motor type. For instance, the expectedmeasurement may represent the motor measurement that should be receivedif the motor-of-interest was of the designated motor type. The expectedmeasurement may be a function of the operating conditions that thetraction motors are currently operating within. For instance, theexpected measurement may be a function of at least one of the excitationfrequency, load of the vehicle system, an apportioned load for themotor-of-interest, or other operating parameters. In particularembodiments, the designated motor type is a high-slip motor or alow-slip motor.

By way of example, during a motoring stage of a propulsion-generatingvehicle that has a per-truck propulsion system, motor measurements for atraction motor may be received. The motor measurements may includetorque measurements when the motor speed and excitation frequency areknown. The torque measurements may be compared to expected measurementsfor low-slip traction motors that are operating at the same motor speedand excitation frequency. If the torque measurements significantlydiffer from the expected measurement, then the traction motor may bedesignated as not being suitable for per-truck operation. For example, amotor measurement may significantly differ from an expected measurementif the motor measurement differs by at least a designated percentage ofthe expected measurement or if a difference between the motormeasurement and the expected measurement exceeds a designated value.

The torque measurements may also be compared to expected measurementsfor other types of traction motors, such as high-slip traction motors.If the torque measurement is approximately equal to the expectedmeasurement, then the traction motor may be designated as a high-sliptraction motor. For example, a motor measurement may be approximatelyequal to an expected measurement if the motor measurement differs byless than a designated percentage of the expected measurement or if adifference between the motor measurement and the expected measurement isless than a designated value.

In some embodiments, the expected measurement may also include aperformance relationship. The performance relationship may be a functionof multiple operating parameters and may be calculated by themeasurement module 282 (FIG. 2). The expected measurement may be anexpected performance relationship, such as those shown in FIGS. 3 and 4.The comparing (at 506) may include comparing one or more features ormetrics of the performance relationships to determine whether themotor-of-interest is a designated motor type. For example, the slope ofthe linear portion of the performance relationship may be calculated andcompared to an expected slope. If the slopes are significantly different(e.g., differ by a designated percentage or the difference exceeds apredetermined value), the motor-of-interest may be labeled as having adifferent motor type.

The method 500 may also include comparing (at 508) the motormeasurements of one traction motor to the motor measurements of theother traction motors. The traction motors may be part of the sametruck, the same propulsion-generating vehicle, or may be from differentpropulsion-generating vehicles. If the measurement of amotor-of-interest significantly differs from the measurements of theother traction motors (e.g., differs by a designated percentage or thedifference exceeds a predetermined value), the motor-of-interest may belabeled as having a different motor type. As one example, a truck of apropulsion-generating vehicle may include first, second, and thirdtraction motors. If the first and third traction motors have torques of3500 ft-lbs and the second fraction motor has a torque of 2000 ft-lbs,then the second traction motor may be designated as having a differentmotor type.

As another example, a vehicle system may include first and secondtraction motors on one propulsion-generating vehicle and third andfourth traction motors on another propulsion-generating vehicle. If thetorques of the first, second, and third traction motors areapproximately equal, but the torque of the fourth traction motor issignificantly different, then the fourth traction motor may bedesignated as having a different motor type. In this example, becausethe traction motors are located on different propulsion-generatingvehicles and, thus, may be affected by different inputs or externalfactors, the torques may be processed to provide values that may becompared.

Based on the comparing (at 506 and/or at 508), the method may alsoinclude determining (at 510) that one or more traction motors areunsuitable for the desired operation, that one or more fraction motorshave a designated motor type, and/or that a group of traction motors aremismatched. A group of traction motors may be mismatched if more thanone motor type exists within the group of traction motors. A group oftraction motors may also be mismatched if at least one of the tractionmotors has been determined to be a designated motor type that is notsuitable for the desired operation of the vehicle. In some embodiments,traction motors may be mismatched if one or more of the traction motorsis not the type of traction motor that was intended to be installed inthe vehicle system. For example, operating plans may be generated basedon designated traction motors of the vehicle system having designatedmotor type(s). As a specific example, an operating plan of a vehiclesystem having two or three traction motors that are electricallyparallel and energized by a common source (e.g., inverter) may be basedon the two or three traction motors being the same type of tractionmotor (e.g., high-slip). If one or more of the traction motors is notthe designated type of traction motor, the traction motors may bemismatched. In some embodiments, the determining (at 510) may includecomparing a motor type that is identified by embodiments set forthherein to the motor type that an operating plan is based on, which mayalso be referred to as the expected motor type. If the motor types donot match, the traction motors may be designated as being mismatched.

In response to determining (at 510), the method 500 may also includeexecuting one or more subsequent actions. The operator of the vehiclesystem may be notified (at 512). For example, a user interface in anoperator's cab may indicate to the operator that a mismatched tractionmotor has been identified. The operator may instruct the vehicle systemto reduce operation (at 516) of the mismatched traction motor or disable(at 518) the mismatched traction motor. The operator may alsocommunicate a message to a remote dispatch office to initiate a plan forreplacing the traction motor. Likewise, a remote control system, such asthe control system 116, may be notified (at 514) that the vehicle systemis operating with a mismatched traction motor. The control system 116may instruct the vehicle system to reduce operation (at 516) of themismatched traction motor or disable (at 518) the mismatched tractionmotor. The control system 116 may also initiate a plan for replacing thetraction motor.

At 520, the control system may automatically request that a modifiedoperating plan be generated. For example, prior to identifying themismatched traction motor, the vehicle system may be operating inaccordance with a designated operating plan. After identifying themismatched motor, a modified operating plan may be generated. Themodified operation plan may at least one of (a) improve an operatingefficiency of the vehicle system in light of the mismatched tractionmotor; (b) reduce the tractive efforts provided by the mismatchedtraction motor; or (c) disable the mismatched traction motor. Forexample, the inverter that energizes mismatched traction motors may beselectively controlled to change the excitation frequency or othercharacteristic that may control performance of the mismatched tractionmotors. The operating plan may be generated by the planning module 284.

In an embodiment, a control system is provided that includes ameasurement module configured to receive motor measurements thatrepresent operating parameters in plural traction motors of a commonvehicle system as the vehicle system propels along a route. The fractionmotors are energized by a common power source and are electricallyparallel with respect to one another. The control system also includesan analysis module that is configured to compare the motor measurementsto one another. The analysis module is configured to determine that thetraction motors include different motor types and are mismatched basedon comparing the motor measurements to one another.

In one aspect, the analysis module is configured to determine that thetraction motors include different motor types based on a difference ofthe motor measurements.

In another aspect, the traction motors are from a commonpropulsion-generating vehicle. In one aspect, the traction motors areinduction motors that are energized by a common inverter.

In another aspect, the analysis module is configured to calculateperformance relationships of the operating parameters for the tractionmotors. The analysis module is configured to determine that the tractionmotors include different motor types based on a comparison of theperformance relationships. In one aspect, the performance relationshipsinclude at least one of a torque-slip relationship, a current-sliprelationship, a torque-speed relationship, or a current-speedrelationship.

In another aspect, in response to determining that the traction motorsinclude different motor types, the control system is configured to atleast one of (a) notify an operator of the vehicle system that thefraction motors include different motor types; (b) notify a remotemonitoring station that the traction motors include different motortypes; (c) reduce tractive efforts of one or more of the tractionmotors; or (d) instruct a planning module to modify an existingoperating plan of the vehicle system based on the fraction motors of thedifferent motor types.

In another aspect, the control system includes a planning module,wherein in response to determining that the traction motors includedifferent motor types, the planning module is configured to modify anexisting operating plan to at least one of (a) improve an operatingefficiency of the vehicle system; (b) reduce the tractive effortsprovided by one or more of the traction motors; or (c) disable one ormore of the fraction motors.

In another aspect, the different motor types include a high-slipinduction motor and a low-slip induction motor.

In an embodiment, a method is provided that includes controlling pluraltraction motors of a vehicle system to propel the vehicle system along aroute. The traction motors are energized by a common power source andare electrically parallel with respect to one another. The method alsoincludes receiving motor measurements that represent operatingparameters of the traction motors as the vehicle system propels alongthe route and comparing the motor measurements to one another. Themethod also includes determining whether the traction motors includedifferent motor types and are mismatched.

In one aspect, the traction motors are from a commonpropulsion-generating vehicle. For example, the traction motors may beinduction motors energized by a common inverter.

In another aspect, the method also includes calculating performancerelationships of the operating parameters for the traction motors anddetermining that the traction motors include different motor types basedon a comparison of the performance relationships.

In another aspect, in response to determining that the traction motorsinclude different motor types. The method also includes at least one of(a) notifying an operator of the vehicle system that the traction motorsinclude different motor types; (b) notifying a remote monitoring stationthat the traction motors include different motor types; (c) reducingtractive efforts of one or more of the traction motors; or (d)instructing a planning module to modify an existing operating plan ofthe vehicle system based on the fraction motors of the different motortypes.

In another aspect, in response to determining that the traction motorsinclude different motor types, the method also includes modifying anexisting operating plan to at least one of (a) improve an operatingefficiency of the vehicle system; (b) reduce the tractive effortsprovided by one or more of the traction motors; or (c) disable one ormore of the traction motors.

In an embodiment, a control system is provided that includes ameasurement module configured to receive motor measurements thatrepresent operating parameters of plural traction motors of a commonvehicle system as the vehicle system propels along a route. The fractionmotors are energized by a common power source and are electricallyparallel with respect to one another. The control system also includesan analysis module that is configured to compare the motor measurementsto an expected measurement. The expected measurement corresponds to adesignated motor type. The analysis module is configured to determinethat at least one of the traction motors is different from thedesignated motor type based on comparing the motor measurements to theexpected measurement.

In another aspect, the operating parameters include at least one of anexcitation frequency, a motor speed, a motor current, a voltage, athermal rise, a torque, or a motor slip of the corresponding fractionmotors.

In another aspect, the expected measurement is one of a range of values,a threshold value, or a baseline value.

In another aspect, the expected measurement is a function of anexcitation frequency received by the plural traction motors.

In another aspect, the plural fraction motors include at least threetraction motors. The analysis module is configured to compare the motormeasurements to one another, wherein the analysis module is configuredto determine that the at least one traction motor is different based oncomparing the motor measurements to one another.

In an embodiment, a control system is provided that includes ameasurement module configured to receive motor measurements thatrepresent operating parameters of plural traction motors of a commonvehicle system as the vehicle system propels along a route. The tractionmotors may be energized by a common power source and be electricallyparallel with respect to one another. The control system also includesan analysis module configured to compare the motor measurements to anexpected measurement. The expected measurement corresponds to adesignated motor type. The analysis module is configured to determinethat at least one of the traction motors is different from thedesignated motor type based on comparing the motor measurements to theexpected measurement.

In one aspect, the operating parameters include at least one of anexcitation frequency, a motor speed, a motor current, a voltage, athermal rise, a torque, or a motor slip of the corresponding fractionmotors.

In another aspect, the expected measurement is one of a range of values,a threshold value, or a baseline value.

In another aspect, the expected measurement is a function of anexcitation frequency received by the plural traction motors.

As used herein, the terms “system” and “module” include a hardwareand/or software system that operates to perform one or more functions.For example, a module or system may include a computer processor,controller, or other logic-based device that performs operations basedon instructions stored on a tangible and non-transitory computerreadable storage medium, such as a computer memory. Alternatively, amodule or system may include a hard-wired device that performsoperations based on hard-wired logic of the device. The modules shown inthe attached figures may represent the hardware that operates based onsoftware or hardwired instructions, the software that directs hardwareto perform the operations, or a combination thereof.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” or “an embodiment” of thepresently described inventive subject matter are not intended to beinterpreted as excluding the existence of additional embodiments thatalso incorporate the recited features. Moreover, unless explicitlystated to the contrary, embodiments “comprising,” “comprises,”“including,” “includes,” “having,” or “has” an element or a plurality ofelements having a particular property may include additional suchelements not having that property.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the inventivesubject matter without departing from its scope. While the dimensionsand types of materials described herein are intended to define theparameters of the inventive subject matter, they are by no meanslimiting and are exemplary embodiments. Many other embodiments will beapparent to one of ordinary skill in the art upon reviewing the abovedescription. The scope of the inventive subject matter should,therefore, be determined with reference to the appended claims, alongwith the full scope of equivalents to which such claims are entitled. Inthe appended claims, the terms “including” and “in which” are used asthe plain-English equivalents of the respective terms “comprising” and“wherein.” Moreover, in the following claims, the terms “first,”“second,” and “third,” etc. are used merely as labels, and are notintended to impose numerical requirements on their objects. Further, thelimitations of the following claims are not written inmeans-plus-function format and are not intended to be interpreted basedon 35 U.S.C. §112, sixth paragraph, unless and until such claimlimitations expressly use the phrase “means for” followed by a statementof function void of further structure.

This written description uses examples to disclose several embodimentsof the inventive subject matter, and also to enable one of ordinaryskill in the art to practice the embodiments of inventive subjectmatter, including making and using any devices or systems and performingany incorporated methods. The patentable scope of the inventive subjectmatter is defined by the claims, and may include other examples thatoccur to one of ordinary skill in the art. Such other examples areintended to be within the scope of the claims if they have structuralelements that do not differ from the literal language of the claims, orif they include equivalent structural elements with insubstantialdifferences from the literal languages of the claims.

The foregoing description of certain embodiments of the presentinventive subject matter will be better understood when read inconjunction with the appended drawings. To the extent that the figuresillustrate diagrams of the functional blocks of various embodiments, thefunctional blocks are not necessarily indicative of the division betweenhardware circuitry. Thus, for example, one or more of the functionalblocks (for example, controllers or memories) may be implemented in asingle piece of hardware (for example, a general purpose signalprocessor, microcontroller, random access memory, hard disk, and thelike). Similarly, the programs may be stand-alone programs, may beincorporated as subroutines in an operating system, may be functions inan installed software package, and the like. The various embodiments arenot limited to the arrangements and instrumentality shown in thedrawings.

What is claimed is:
 1. A control system comprising: a measurement moduleconfigured to receive motor measurements that represent operatingparameters in plural traction motors of a common vehicle system as thevehicle system propels along a route, the fraction motors beingenergized by a common power source and being electrically parallel withrespect to one another; and an analysis module configured to compare themotor measurements to one another, the analysis module configured todetermine that the traction motors include different motor types and aremismatched based on comparing the motor measurements to one another. 2.The control system of claim 1, wherein the analysis module is configuredto determine that the traction motors include different motor typesbased on a difference of the motor measurements.
 3. The control systemof claim 1, wherein the traction motors are from a commonpropulsion-generating vehicle.
 4. The control system of claim 3, whereinthe traction motors are induction motors that are energized by a commoninverter.
 5. The control system of claim 1, wherein the analysis moduleis configured to calculate performance relationships of the operatingparameters for the traction motors, the analysis module configured todetermine that the traction motors include different motor types basedon a comparison of the performance relationships.
 6. The control systemof claim 5, wherein the performance relationships include at least oneof a torque-slip relationship, a current-slip relationship, atorque-speed relationship, or a current-speed relationship.
 7. Thecontrol system of claim 1, wherein, in response to determining that thetraction motors include different motor types, the control system isconfigured to at least one of (a) notify an operator of the vehiclesystem that the traction motors include different motor types; (b)notify a remote monitoring station that the traction motors includedifferent motor types; (c) reduce tractive efforts of one or more of thetraction motors; or (d) instruct a planning module to modify an existingoperating plan of the vehicle system based on the traction motors of thedifferent motor types.
 8. The control system of claim 1, furthercomprising a planning module, wherein in response to determining thatthe traction motors include different motor types, the planning moduleis configured to modify an existing operating plan to at least one of(a) improve an operating efficiency of the vehicle system; (b) reducethe tractive efforts provided by one or more of the traction motors; or(c) disable one or more of the fraction motors.
 9. The control system ofclaim 1, wherein the different motor types include a high-slip inductionmotor and a low-slip induction motor.
 10. A method comprising:controlling plural traction motors of a vehicle system to propel thevehicle system along a route, the traction motors being energized by acommon power source and being electrically parallel with respect to oneanother; receiving motor measurements that represent operatingparameters of the traction motors as the vehicle system propels alongthe route; comparing the motor measurements to one another; anddetermining whether the traction motors include different motor typesand are mismatched.
 11. The method of claim 10, wherein the tractionmotors are from a common propulsion-generating vehicle.
 12. The methodof claim 11, wherein the traction motors are induction motors energizedby a common inverter.
 13. The method of claim 10, further comprisingcalculating performance relationships of the operating parameters forthe traction motors and determining that the traction motors includedifferent motor types based on a comparison of the performancerelationships.
 14. The method of claim 10, wherein, in response todetermining that the traction motors include different motor types, themethod further comprises at least one of (a) notifying an operator ofthe vehicle system that the traction motors include different motortypes; (b) notifying a remote monitoring station that the tractionmotors include different motor types; (c) reducing tractive efforts ofone or more of the traction motors; or (d) instructing a planning moduleto modify an existing operating plan of the vehicle system based on thetraction motors of the different motor types.
 15. The method of claim10, wherein, in response to determining that the traction motors includedifferent motor types, the method further comprises modifying anexisting operating plan to at least one of (a) improve an operatingefficiency of the vehicle system; (b) reduce the tractive effortsprovided by one or more of the traction motors; or (c) disable one ormore of the traction motors.
 16. A control system comprising: ameasurement module configured to receive motor measurements thatrepresent operating parameters of plural fraction motors of a commonvehicle system as the vehicle system propels along a route, the fractionmotors being energized by a common power source and being electricallyparallel with respect to one another; and an analysis module configuredto compare the motor measurements to an expected measurement, theexpected measurement corresponding to a designated motor type, theanalysis module configured to determine that at least one of thetraction motors is different from the designated motor type based oncomparing the motor measurements to the expected measurement.
 17. Thecontrol system of claim 16, wherein the operating parameters include atleast one of an excitation frequency, a motor speed, a motor current, avoltage, a thermal rise, a torque, or a motor slip of the correspondingtraction motors.
 18. The control system of claim 16, wherein theexpected measurement is one of a range of values, a threshold value, ora baseline value.
 19. The control system of claim 16, wherein theexpected measurement is a function of an excitation frequency receivedby the plural fraction motors.
 20. The control system of claim 16,wherein the plural fraction motors include at least three tractionmotors, the analysis module configured to compare the motor measurementsto one another, wherein the analysis module is configured to determinethat the at least one traction motor is different based on comparing themotor measurements to one another.